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Peluso P, Chankvetadze B. Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers. Chem Rev 2022; 122:13235-13400. [PMID: 35917234 DOI: 10.1021/acs.chemrev.1c00846] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as "multistep" processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.
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Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB, CNR, Sede secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, I-07100 Sassari, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Avenue 3, 0179 Tbilisi, Georgia
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Ružena Č, Jindra V, Renáta H. Chirality of β2-agonists. An overview of pharmacological activity, stereoselective analysis, and synthesis. OPEN CHEM 2020. [DOI: 10.1515/chem-2020-0056] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Abstractβ2-Agonists (β2-adrenergic agonists, bronchodilatants, and sympathomimetic drugs) are a group of drugs that are mainly used in asthma and obstructive pulmonary diseases. In practice, the substances used to contain one or more stereogenic centers in their structure and their enantiomers exhibit different pharmacological properties. In terms of bronchodilatory activity, (R)-enantiomers showed higher activity. The investigation of stereoselectivity in action and disposition of chiral drugs together with the preparation of pure enantiomer drugs calls for efficient stereoselective analytical methods. The overview focuses on the stereoselectivity in pharmacodynamics and pharmacokinetics of β2-agonists and summarizes the stereoselective analytical methods for the enantioseparation of racemic beta-agonists (HPLC, LC-MS, GC, TLC, CE). Some methods of the stereoselective synthesis for β2-agonists preparation are also presented.
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Affiliation(s)
- Čižmáriková Ružena
- Department of Chemical Theory of Drugs, Faculty of Pharmacy, Comenius University in Bratislava, Odbojárov 10, 832 32 Bratislava, Slovakia
| | - Valentová Jindra
- Department of Chemical Theory of Drugs, Faculty of Pharmacy, Comenius University in Bratislava, Odbojárov 10, 832 32 Bratislava, Slovakia
| | - Horáková Renáta
- Department of Chemical Theory of Drugs, Faculty of Pharmacy, Comenius University in Bratislava, Odbojárov 10, 832 32 Bratislava, Slovakia
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3
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Moser AC, Trenhaile S, Frankenberg K. Studies of antibody-antigen interactions by capillary electrophoresis: A review. Methods 2018; 146:66-75. [DOI: 10.1016/j.ymeth.2018.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 11/25/2022] Open
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4
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Farcaş E, Bouckaert C, Servais AC, Hanson J, Pochet L, Fillet M. Partial filling affinity capillary electrophoresis as a useful tool for fragment-based drug discovery: A proof of concept on thrombin. Anal Chim Acta 2017; 984:211-222. [DOI: 10.1016/j.aca.2017.06.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 06/13/2017] [Accepted: 06/25/2017] [Indexed: 01/19/2023]
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Quality by design in the chiral separation strategy for the determination of enantiomeric impurities: development of a capillary electrophoresis method based on dual cyclodextrin systems for the analysis of levosulpiride. J Chromatogr A 2014; 1380:177-85. [PMID: 25582483 DOI: 10.1016/j.chroma.2014.12.065] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/18/2014] [Accepted: 12/21/2014] [Indexed: 11/21/2022]
Abstract
Quality by design (QbD) concepts, in accordance with International Conference on Harmonisation Pharmaceutical Development guideline Q8(R2), represent an innovative strategy for the development of analytical methods. In this paper QbD principles have been comprehensively applied in the set-up of a capillary electrophoresis method aimed to quantify enantiomeric impurities. The test compound was the chiral drug substance levosulpiride (S-SUL) and the developed method was intended to be used for routine analysis of the pharmaceutical product. The target of analytical QbD approach is to establish a design space (DS) of critical process parameters (CPPs) where the critical quality attributes (CQAs) of the method have been assured to fulfil the desired requirements with a selected probability. QbD can improve the understanding of the enantioseparation process, including both the electrophoretic behavior of enantiomers and their separation, therefore enabling its control. The CQAs were represented by enantioresolution and analysis time. The scouting phase made it possible to select a separation system made by sulfated-β-cyclodextrin and a neutral cyclodextrin, operating in reverse polarity mode. The type of neutral cyclodextrin was included among other CPPs, both instrumental and related to background electrolyte composition, which were evaluated in a screening phase by an asymmetric screening matrix. Response surface methodology was carried out by a Doehlert design and allowed the contour plots to be drawn, highlighting significant interactions between some of the CPPs. DS was defined by applying Monte-Carlo simulations, and corresponded to the following intervals: sulfated-β-cyclodextrin concentration, 9-12 mM; methyl-β-cyclodextrin concentration, 29-38 mM; Britton-Robinson buffer pH, 3.24-3.50; voltage, 12-14 kV. Robustness of the method was examined by a Plackett-Burman matrix and the obtained results, together with system repeatability data, led to define a method control strategy. The method was validated and was finally applied to determine the enantiomeric purity of S-SUL in pharmaceutical dosage forms.
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Sanghvi M, Ramamoorthy A, Strait J, Wainer IW, Moaddel R. Development and validation of a sensitive LC-MS/MS method for the determination of fenoterol in human plasma and urine samples. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 933:37-43. [PMID: 23872161 PMCID: PMC3767123 DOI: 10.1016/j.jchromb.2013.06.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 06/07/2013] [Accepted: 06/12/2013] [Indexed: 10/26/2022]
Abstract
Due to the lack of sensitivity in current methods for the determination of fenoterol (Fen), a rapid LC-MS/MS method was developed for the determination of (R,R')-Fen and (R,R';S,S')-Fen in plasma and urine. The method was fully validated and was linear from 50pg/ml to 2000pg/ml for plasma and from 2.500ng/ml to 160ng/ml for urine with a lower limit of quantitation of 52.8pg/ml in plasma. The coefficient of variation was <15% for the high QC standards and <10% for the low QC standards in plasma and was <15% for the high and low QC standards in urine. The relative concentrations of (R,R')-Fen and (S,S')-Fen were determined using a chirobiotic T chiral stationary phase. The method was used to determine the concentration of (R,R')-Fen in plasma and urine samples obtained in an oral cross-over study of (R,R')-Fen and (R,R';S,S')-Fen formulations. The results demonstrated a potential pre-systemic enantioselective interaction in which the (S,S')-Fen reduces the sulfation of the active (R,R')-Fen. The data suggest that a non-racemic mixture of the Fen enantiomers may provide better bioavailability of the active (R,R')-Fen for use in the treatment of cardiovascular disease.
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Affiliation(s)
- M. Sanghvi
- Laboratory of Clinical Investigation, Division of Intramural Research Programs, National institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - A. Ramamoorthy
- Laboratory of Clinical Investigation, Division of Intramural Research Programs, National institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - J. Strait
- Laboratory of Cardiovascular Sciences, Division of Intramural Research Programs, National Institute on Aging, National Institutes of Health, Baltimore, MD. 21224, USA
| | - I. W. Wainer
- Laboratory of Clinical Investigation, Division of Intramural Research Programs, National institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - R. Moaddel
- Laboratory of Clinical Investigation, Division of Intramural Research Programs, National institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Amin NC, Blanchin MD, Aké M, Fabre H. Capillary electrophoresis methods for the analysis of antimalarials. Part I. Chiral separation methods. J Chromatogr A 2012; 1264:1-12. [DOI: 10.1016/j.chroma.2012.09.057] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 09/10/2012] [Accepted: 09/15/2012] [Indexed: 11/30/2022]
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Quirino JP, Aranas AT. On-line sample concentration via micelle to solvent stacking of cations prepared with aqueous organic solvents in capillary electrophoresis. Electrophoresis 2012; 33:2167-75. [DOI: 10.1002/elps.201200023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Fakhari AR, Tabani H, Nojavan S, Abedi H. Electromembrane extraction combined with cyclodextrin-modified capillary electrophoresis for the quantification of trimipramine enantiomers. Electrophoresis 2012; 33:506-15. [DOI: 10.1002/elps.201100426] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Zaidi SA, Lee SM, Cheong WJ. Open tubular capillary columns with basic templates made by the generalized preparation protocol in capillary electrochromatography chiral separation and template structural effects on chiral separation capability. J Chromatogr A 2011; 1218:1291-9. [DOI: 10.1016/j.chroma.2010.12.117] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 12/27/2010] [Accepted: 12/31/2010] [Indexed: 11/29/2022]
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Ullrich T, Wesenberg D, Bleuel C, Krauss GJ, Schmid MG, Weiss M, Gübitz G. Chiral separation of the β2-sympathomimetic fenoterol by HPLC and capillary zone electrophoresis for pharmacokinetic studies. Biomed Chromatogr 2010; 24:1125-9. [DOI: 10.1002/bmc.1415] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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12
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18 Coupling CE and microchip-based devices with mass spectrometry. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s0149-6395(07)00018-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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13
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Terabe S. Micellar electrokinetic chromatography for high-performance analytical separation. CHEM REC 2008; 8:291-301. [DOI: 10.1002/tcr.20156] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Martínez-Gómez MA, Sagrado S, Villanueva-Camañas RM, Medina-Hernández MJ. Enantiomeric quality control of antihistamines in pharmaceuticals by affinity electrokinetic chromatography with human serum albumin as chiral selector. Anal Chim Acta 2007; 592:202-9. [PMID: 17512827 DOI: 10.1016/j.aca.2007.04.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 04/04/2007] [Accepted: 04/16/2007] [Indexed: 10/23/2022]
Abstract
The present paper deals with the enantiomeric separation of six antihistaminic enantiomers by affinity electrokinetic chromatography (AEKC)-partial filling technique using human serum albumin (HSA) as chiral selector. A multivariate optimization approach of the most critical experimental variables in enantioresolution, running pH, HSA concentration and HSA plug length (SPL) was carried out since there are interactions between variables that could not be considered in an univariate optimization. The estimated and experimental resolution values obtained for antihistaminic enantiomers varied from 1.13 (for orphenadrine) to 2.15 (for brompheniramine). The optimum experimental conditions for enantioresolution of each compound were: brompheniramine, pH 8.5, [HSA] 180 microM, SPL 180 s; chlorcyclizine, pH 6.5, [HSA] 180 microM, SPL 150 s; chlorpheniramine, pH 8.25, [HSA] 160 microM, SPL 150 s; hydroxyzine, pH 7.0, [HSA] 180 microM, SPL 150 s; and orphenadrine, pH 7.8, [HSA] 160 microM, SPL 150 s. pH and the quadratic term of pH seem to be the most critical factors that determine enantioresolution of antihistamines. The validity of the developed methodologies to enantiomeric quality control of antihistamines in pharmaceutical formulations is demonstrated analyzing the content of brompheniramine, chlorpheniramine and hyroxyzine enantiomers in commercially available pharmaceutical formulations containing racemic mixtures of compounds. Resolution, accuracy, reproducibility, cost and sample throughput of the proposed methodologies make them suitable for quality control of the enantiomeric composition of antihistamines in pharmaceutical preparations.
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Affiliation(s)
- M A Martínez-Gómez
- Departamento de Química Analítica, Facultat de Farmacia, Universitat de València, C/Vicent Andrés Estellés s/n, E-46100 Burjassot, Valencia, Spain
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Martínez-Gómez MA, Sagrado S, Villanueva-Camañas RM, Medina-Hernández MJ. Enantioseparation of phenotiazines by affinity electrokinetic chromatography using human serum albumin as chiral selector: application to enantiomeric quality control in pharmaceutical formulations. Anal Chim Acta 2006; 582:223-8. [PMID: 17386496 DOI: 10.1016/j.aca.2006.09.036] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 09/18/2006] [Accepted: 09/19/2006] [Indexed: 10/24/2022]
Abstract
Nowadays, there is a special interest within the pharmaceutical laboratories to develop single enantiomer formulations and consequently a need for analytical methods to determine the enantiomeric purity of drugs. The present paper deals with the enantiomeric separation of promethazine and trimeprazine enantiomers by affinity electrokinetic chromatography (AEKC)-partial filling technique using human serum albumin (HSA) as chiral selector. A multivariate optimization of the most critical experimental variables in enantioresolution, running pH, HSA concentration and plug length, is carried out to obtain enantioresolution of promethazine and trimeprazine. The estimated maximum and optimum resolution of trimeprazine and prometazine enantiomers (Rs=1.74 and 2.01, respectively) corresponded to the following experimental conditions: pH 7.5; [HSA] 170 microM and plug length 190 s and pH 7.6; [HSA] 170 microM and plug length 170 s, for trimeprazine and prometazine, respectively. The developed methodologies were applied for the enantiomeric quality control of promethazine and trimeprazine enantiomers in commercially available pharmaceutical formulations. Resolution, accuracy, reproducibility, cost and sample throughput of the proposed methodologies make it suitable for quality control of the enantiomeric composition of promethazine and trimeprazine in pharmaceutical preparations.
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Affiliation(s)
- María Amparo Martínez-Gómez
- Departamento de Química Analítica, Facultat de Farmacia, Universitat de València, C/Vicent Andrés Estellés s/n, E-46100 Burjassot, Valencia, Spain
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Rudaz S, Geiser L, Souverain S, Prat J, Veuthey JL. Rapid stereoselective separations of amphetamine derivatives with highly sulfated γ-cyclodextrin. Electrophoresis 2005; 26:3910-20. [PMID: 16167308 DOI: 10.1002/elps.200500177] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The highly sulfated gamma-CD (HS-gamma-CD) is a chiral selector widely used in CE for the enantioseparation of pharmaceutical compounds. This paper investigated different approaches to reduce the stereoselective analysis time of amphetamine (AT) derivatives according to the chiral selector concentration in the BGE. With high HS-gamma-CD concentration, tested analytes were separated in 3.5 min as anionic complexes with short-end injection technique in reversed polarity mode. However, this procedure presented some limitations in terms of efficiency and resolution, excessive Joule heating and poor compatibility with MS detection. With low HS-gamma-CD concentration, compounds were separated as cations. Conventional approaches to reduce CE analysis time demonstrated critical resolution between some analytes. Therefore, the use of the partial-filling technique compatible with MS detection was carried out. Under optimized conditions, the analysis time for the chiral separation of seven AT like compounds was reduced to 6 min. Moreover, sensitivity of CE-MS was sufficient for the determination of ATs in plasma following a simple liquid-liquid extraction.
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Affiliation(s)
- Serge Rudaz
- Laboratory of Pharmaceutical Analytical Chemistry, School of Pharmaceutical Sciences, EPGL, University of Geneva, Geneva, Switzerland.
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Brown A, Desharnais R, Roy BC, Malik S, Gomez FA. Optimization of conditions for flow-through partial-filling affinity capillary electrophoresis to estimate binding constants of ligands to receptors. Anal Chim Acta 2005. [DOI: 10.1016/j.aca.2005.03.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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18
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Herbert BJ, Carpenter HE, Kane-Maguire NA, Wheeler JF. Use of chiral capillary electrophoresis and circular dichroism for the determination of absolute values of Δε for diimine transition metal complexes. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.03.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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Martı́nez-Pla JJ, Martı́n-Biosca Y, Sagrado S, Villanueva-Camañas RM, Medina-Hernández MJ. Fast enantiomeric separation of propranolol by affinity capillary electrophoresis using human serum albumin as chiral selector: application to quality control of pharmaceuticals. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2003.11.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Azad M, Silverio C, Zhang Y, Villareal V, Gomez FA. On-column synthesis coupled to affinity capillary electrophoresis for the determination of binding constants of peptides to glycopeptide antibiotics. J Chromatogr A 2004; 1027:193-202. [PMID: 14971503 DOI: 10.1016/j.chroma.2003.10.102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Binding constants of the glycopeptide antibiotics teicoplanin (Teic), ristocetin (Rist), and vancomycin (Van), and their derivatives to D-Ala-D-Ala terminus peptides were determined by on-column ligand and receptor synthesis coupled to affinity capillary electrophoresis (ACE) or partial filling ACE (PFACE). In the first technique, 9-fluorenylmethoxycarbonyl (Fmoc)-amino acid-D-Ala-D-Ala species are first synthesized using on-column techniques. The initial sample plug contains a D-Ala-D-Ala terminus peptide and two non-interacting standards. Plugs two and three contain solutions of Fmoc-amino acid-N-hydroxysuccinimide (NHS) ester and buffer, respectively. Upon electrophoresis, the initial D-Ala-D-Ala peptide reacts with the Fmoc-amino acid NHS ester yielding the Fmoc-amino acid D-Ala-D-Ala peptide. Continued electrophoresis results in the overlap of the glycopeptide in the running buffer and the plug of Fmoc-amino acid-D-Ala-D-Ala peptide and non-interacting markers. Subsequent analysis of the change in the electrophoretic mobility (mu) or relative migration time ratio (RMTR) of the peptide relative to the non-interacting standards, as a function of the concentration of the antibiotic, yields a value for the binding constant. In the second technique, derivatives of the glycopeptides Teic and Rist are first synthesized on-column before analysis by ACE or PFACE. After the column has been partially filled with increasing concentrations of D-Ala-D-Ala terminus peptides, a plug of buffer followed by two separate plugs of reagents are injected. The order of the reagent plugs containing the antibiotic and two non-interacting standards and the anhydride varies with the charge of the glycopeptide. Upon electrophoresis, the antibiotic reacts with the anhydride yielding a derivative of Teic or Rist. Continued electrophoresis results in the overlap of the derivatized antibiotic and the plug of D-Ala-D-Ala peptide. Analysis of the change in RMTR of the new glycopeptide relative to the non-interacting standards, as a function of the concentration of the D-Ala-D-Ala ligand yields a value for the binding constant.
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Affiliation(s)
- Maryam Azad
- Department of Chemistry, and Biochemistry, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032-8202, USA
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Azad M, Hernandez L, Plazas A, Rudolph M, Gomez FA. Determination of binding constants between the antibiotic ristocetin A and D-Ala-D-Ala terminus peptides by affinity capillary electrophoresis. Chromatographia 2003. [DOI: 10.1007/bf02492405] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Chankvetadze B, Burjanadze N, Breitkreutz J, Bergander K, Bergenthal D, Kataeva O, Fröhlich R, Luftmann H, Blaschke G. Mechanistic study on the opposite migration order of the enantiomers of ketamine with α- and β-cyclodextrin in capillary electrophoresis. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20021101)25:15/17%3c1155::aid-jssc1155%3e3.0.co;2-m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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23
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Chankvetadze B, Burjanadze N, Breitkreutz J, Bergander K, Bergenthal D, Kataeva O, Fröhlich R, Luftmann H, Blaschke G. Mechanistic study on the opposite migration order of the enantiomers of ketamine with α- and β-cyclodextrin in capillary electrophoresis. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20021101)25:15/17<1155::aid-jssc1155>3.0.co;2-m] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Heegaard NHH, Nissen MH, Chen DDY. Applications of on-line weak affinity interactions in free solution capillary electrophoresis. Electrophoresis 2002; 23:815-22. [PMID: 11920866 DOI: 10.1002/1522-2683(200203)23:6<815::aid-elps815>3.0.co;2-v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on-line affinity capillary electrophoresis approach is feasible when the migration of complexed molecules is different from the migration of free molecules and when separation conditions are nondenaturing. In this review, we focus on applying weak interactions as tools to enhance the separation of closely related molecules, e.g., drug enantiomers and on using capillary electrophoresis to characterize such interactions quantitatively. We describe the equations for binding isotherms, illustrate how selectivity can be manipulated by varying the additive concentrations, and show how the methods may be used to estimate binding constants. On-line affinity capillary electrophoresis methods are especially valuable for enantiomeric separations and for functional characterization of the contents of biological samples that are only available in minute quantities.
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Affiliation(s)
- Niels H H Heegaard
- Department of Autoimmunology, Bldg. 81, Rm. 536, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
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Hou JG, Liu HL, Du XZ, Han XQ, Deng HL, Gao JZ. CHIRAL SEPARATION OF ABSCISIC ACID ENANTIOMERS BY CAPILLARY ZONE ELECTROPHORESIS USING CYCLODEXTRINS AND THEIR DERIVATIVES AS CHIRAL SELECTORS. ANAL LETT 2002. [DOI: 10.1081/al-120015005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Zhang Y, Kodama C, Zurita C, Gomez FA. On-column ligand synthesis coupled to partial-filling affinity capillary electrophoresis to estimate binding constants of ligands to a receptor. J Chromatogr A 2001; 928:233-41. [PMID: 11587342 DOI: 10.1016/s0021-9673(01)01117-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper describes a two-step procedure whereby on-column ligand synthesis and partial-filling affinity capillary electrophoresis (PFACE) are sequentially coupled to each other to determine the binding constants of 9-fluorenylmethoxy carbonyl (Fmoc)-amino acid-D-Ala-D-Ala species to vancomycin (Van) from Streptomyces orientalis. In this technique four separate plugs of sample are injected onto the capillary column and electrophoresed. The initial sample plug contains a D-Ala-D-Ala terminus peptide and two non-interacting standards. Plugs two and three contain solutions of Fmoc-amino acid-N-hydroxysuccinimide (NHS) ester and running buffer, respectively. The fourth sample plug contains an increasing concentration of Van partially-filled onto the capillary column. Upon electrophoresis the initial D-Ala-D-Ala peptide reacts with the Fmoc-amino acid NHS ester yielding the Fmoc-amino acid D-Ala-D-Ala peptide. Continued electrophoresis results in the overlap of the plugs of Van and Fmoc-amino acid-D-Ala-D-Ala peptide and non-interacting markers. Analysis of the change in the relative migration time ratio of the Fmoc-amino acid-D-Ala-D-Ala peptide relative to the non-interacting standards, as a function of the concentration of Van, yields a value for the binding constant. These values agree well with those estimated using other binding and ACE techniques.
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Affiliation(s)
- Y Zhang
- Department of Chemistry and Biochemistry, California State University, Los Angeles, 90032-8202, USA
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27
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Abstract
A review is presented that surveys the basic theory of direct separation of enantiomers by capillary electrophoretic (CE) techniques. These separations are based on the formation of diastereomeric complexes between the enantiomeric analytes and a chiral selector added to the electrolyte solution. The review covers a comprehensive treatment of the equations needed for optimization of selectivity coefficients, resolution and analysis time in the zone electrophoretic mode. In this context, it takes into account combined equilibria of complexation and protonation/deprotonation as well as complexation and paritition into micelles. On the basis of these equations, the benefits of charged selectors and the optimization potential inherent to pH tuning can be documented. In addition, the review deals with some basic aspects of chiral isoelectric focusing and briefly discusses indirect enantioseparation. In a subsequent section a survey is given on particularfeatures of the various types of chiral selectors. Finally, the recent developments in preparative enantioseparation in continuous free-flow system and by use of isoelectric membranes are discussed.
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Affiliation(s)
- A Rizzi
- Institute of Analytical Chemistry, University of Vienna, Austria.
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28
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Rudaz S, Cherkaoui S, Gauvrit JY, Lantéri P, Veuthey JL. Experimental designs to investigate capillary electrophoresis-electrospray ionization-mass spectrometry enantioseparation with the partial-filling technique. Electrophoresis 2001; 22:3316-26. [PMID: 11589296 DOI: 10.1002/1522-2683(200109)22:15<3316::aid-elps3316>3.0.co;2-r] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An experimental design approach is described to evaluate the main electrophoretic parameters involved in the enantioseparation of pharmaceuticals by capillary electrophoresis (CE) coupled to electrospray ionization-mass spectrometry (ESI-MS). For all experiments, the partial-filling technique was applied to avoid the chiral selector entering in the mass spectrometer ion source with a negative effect on the electrospray performance. To carry out enantioseparation, a volatile buffer constituted of 20 mM ammonium acetate at pH 4.0, and a polyvinyl alcohol-coated capillary were used. Methadone was employed as the model compound and three different cyclodextrins (CDs), namely sulfobutyl ether-beta-CD, carboxymethylated-beta-CD and hydroxypropyl-beta-CD, were selected in order to study the countercurrent process. Two different experimental designs were chosen: (i) a full-factorial design to examine the effects and significance of the investigated factors, and (ii) a central composite face-centered design to establish the mathematical model of the selected responses in function of experimental factors. The chiral selector concentration, percentage of the capillary filled with the chiral selector, and drying gas nebulization pressure were three relevant factors taken into consideration. For each CD, the methadone enantiomeric resolution, apparent selectivity, and migration time of the second enantiomer were established as responses. The latter were systematically related to experimental parameters with the help of multiple linear regression. It is noteworthy that the behaviour was different in function of the chiral selector charge. Results revealed that the nebulization pressure involved in the electrospray process and the CD concentration had a significant effect on the enantiomeric resolution, while the effect of the separation zone length was less pronounced. Finally, response surfaces were drawn from the mathematical model and experimental conditions were selected to allow a robust determination of methadone enantiomers by CE-MS.
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Affiliation(s)
- S Rudaz
- Laboratory of Pharmaceutical Analytical Chemistry, University of Geneva, Switzerland
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29
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Matsunaga H, Haginaka J. Separation of basic drug enantiomers by capillary electrophoresis using ovoglycoprotein as a chiral selector: comparison of chiral resolution ability of ovoglycoprotein and completely deglycosylated ovoglycoprotein. Electrophoresis 2001; 22:3251-6. [PMID: 11589287 DOI: 10.1002/1522-2683(200109)22:15<3251::aid-elps3251>3.0.co;2-i] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Separations of basic drug enantiomers by capillary electrophoresis (CE) using ovoglycoprotein (OGCHI) as a chiral selector are described. The effects of running buffer pH and 2-propanol content on the migration times and resolution of basic drug enantiomers were examined using a linear polyacrylamide-coated capillary. High resolution of basic drug enantiomers was attained using a mixture of 50 mM sodium phosphate buffer (pH 4.5-6.0) and 2-propanol (5-30%) including 50 microM OGCHI. It was found that ionic and hydrophobic interactions could work for the recognition of basic drug enantiomers. Further, we compared the chiral resolution ability of OGCHI with that of completely deglycosylated OGCHI (cd-OGCHI) using them as chiral selectors in CE. OGCHI showed higher resolution for basic drug enantiomers tested than cd-OGCHI. The results suggest that the chiral recognition site(s) for OGCHI exists on the protein domain of OGCHI.
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Affiliation(s)
- H Matsunaga
- Faculty of Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya, Hyogo, Japan
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30
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Grard S, Morin PH, Dreux M, Ribet JP. Efficient applications of capillary electrophoresis-tandem mass spectrometry to the analysis of adrenoreceptor antagonist enantiomers using a partial filling technique. J Chromatogr A 2001; 926:3-10. [PMID: 11554417 DOI: 10.1016/s0021-9673(01)01005-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Throughout the separation of chiral basic drugs by capillary electrophoresis (CE) with neutral hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as chiral selector, the sensitivity of detection can be improved by using tandem mass spectrometric (MS-MS) detection with a partial filling technique rather than with UV spectrometric detection. Prior to sample injection. the capillary was partly filled with HP-beta-CD dissolved in volatile ammonium formate buffer (pH 4, ionic strength 50 mM). The effects of modifying the HP-beta-CD concentration in the selector zone and the length of the separation zone on the enantioresolution and the signal-to-noise ratio of the pseudo-molecular MH+ ion were investigated. For a given selector zone length, as the concentration of the neutral cyclodextrin increases, the resolution between enantiomers becomes higher (the opposite of the behavior of the signal-to-noise ratio) and then reaches an optimum value. The decrease of the selector zone length lowered the resolution between the enantiomers but increased peak efficiencies and signal-to-noise ratio values. Accordingly, partial capillary filling at 80% (v/v) and 10 mM concentration of HP-beta-CD was selected as a suitable compromise between resolution and sensitivity of MS detection. Limits of detection for each adrenoreceptor antagonist enantiomer were 5 ng/ml (0.02 microM) in CE-MS-MS instead of 150 ng/ml (0.60 microM) in CE-UV, which enhances sensitivity by a factor of 30.
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Affiliation(s)
- S Grard
- Institut de Chimie Organique et Analytique, CNRS UMR 6005, Université d'Orléans, France
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31
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Harris JE, Desai N, Seaver KE, Watson RT, Kane-Maguire NA, Wheeler JF. Chiral separations of transition metal complexes using capillary zone electrophoresis. J Chromatogr A 2001; 919:427-36. [PMID: 11442050 DOI: 10.1016/s0021-9673(01)00820-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Several buffer additives that may facilitate chiral separation for optically active transition metal (TM) systems are investigated using capillary zone electrophoresis. The TM complexes evaluated exhibit considerable heterogeneity with respect to total complex charge (0 to 4+), ligand type, and identity of the central metal including Ru2+, Ni2+, Cr3+, and Co3+, threo-D[+]-Isocitrate, potassium antimonyl-d-tartrate and dibenzoyl-L-tartrate are identified as the most efficient chiral selectors. Interestingly, TM complexes exhibiting a (3+) total complex charge exhibit a reversal of enantiomer elution order versus all other complexes when separated using the tartrate additives. Operating parameters including pH, temperature, and capillary length are discussed, and chiral separations of complex mixtures are demonstrated.
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Affiliation(s)
- J E Harris
- Department of Chemistry, Furman University, Greenville, SC 29613-1120, USA
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32
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Michalke D, Kolb S, Welsch T. Influence of buffer zone concentrations on efficiency in partial filling micellar electrokinetic chromatography. J Chromatogr A 2001; 916:113-22. [PMID: 11382283 DOI: 10.1016/s0021-9673(00)01237-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The potential of counter pressure-moderated partial filling micellar electrokinetic chromatography (PF-MEKC) was investigated in this work. Plate numbers of homologous omega-phenylalcohols were measured in a two-plug PF-MEKC system varying the concentrations and hence the ionic strengths of the background buffer compared to the sodium dodecyl sulfate-containing separation buffer and the counter pressure on the cathodic buffer reservoir. It was observed that plate numbers are strongly influenced by both the buffer concentrations and the counter pressure. Highest plate numbers were obtained with a buffer system where the concentrations are adjusted such that the electroosmotic flow velocities in both zones are equal. Differences in the local electroosmotic flow velocities of the zones caused by different buffer concentrations are responsible for tremendously reduced plate numbers. The efficiency drop is explained in several models by the formation of an intersegmental pressure which produces a parabolically shaped laminar flow component in both zones. Thus, the electroosmotic plug-like flow profile is distorted and the efficiency is reduced. The effect of counter pressure on efficiency turned out to be very complex in dependence on the buffer system applied.
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Affiliation(s)
- D Michalke
- University of Ulm, Department of Analytical and Environmental Chemistry, Germany
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33
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De Lorenzi E, Massolini G, Molinari P, Galbusera C, Longhi R, Marinzi C, Consonni R, Chiari M. Chiral capillary electrophoresis and nuclear magnetic resonance investigation on the structure-enantioselectivity relationship in synthetic cyclopeptides as chiral selectors. Electrophoresis 2001; 22:1373-84. [PMID: 11379960 DOI: 10.1002/1522-2683(200105)22:7<1373::aid-elps1373>3.0.co;2-o] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In the present work, synthetic cyclohexa- and cycloheptapeptides previously singled out by a combinatorial chemistry approach have been evaluated as chiral selectors in capillary electrophoresis. By applying the countercurrent migration technique and employing a new adsorbed coating, a series of dinitrophenyl amino acids as well as some chiral compounds of pharmaceutical interest have been evaluated for enantiorecognition. The results thus obtained led to a deeper investigation of the chiral discrimination process, by carrying out nuclear magnetic resonance (NMR) studies on selected cyclopeptide-analyte complexes. These studies shed light on the chemical groups involved in the analyte-selector interaction and provided useful information for a wider application of these cyclopeptides in the separation of other drug enantiomers.
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Affiliation(s)
- E De Lorenzi
- Department of Pharmaceutical Chemistry, University of Pavia, Italy.
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34
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Tanaka Y, Terabe S. Recent advances in enantiomer separations by affinity capillary electrophoresis using proteins and peptides. ACTA ACUST UNITED AC 2001; 48:103-16. [PMID: 11356482 DOI: 10.1016/s0165-022x(01)00143-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Enantiomer separations by capillary electrophoresis (CE), using proteins as chiral selectors--affinity capillary electrophoresis (ACE) with free solutions and capillary electrochromatography (CEC)--with protein immobilized capillaries, are reviewed. The separation principle, recent advances in this field and some interesting topics are presented. In ACE, various enantiomer separations have been already reported using either plasma proteins or egg white ones. Miscellaneous proteins were also explored in the last few years. On the contrary, only a limited number of enantiomer separations have been successfully achieved in CEC. CEC is not yet mature enough to date, and further investigations, such as efficiency, durability and reproducibility of capillaries, will be necessary for the use of routine analyses. The study of enantioselective drug-protein binding is important in pharmaceutical developments. Some applications including high-performance CE/frontal analysis (HPCE/FA) are introduced in this paper.
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Affiliation(s)
- Y Tanaka
- Department of Analytical Chemistry, Nippon Boehringer Ingelheim Co. Ltd., 3-10-1, Yato, Hyogo 666-0193, Kawanishi, Japan
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35
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Chankvetadz B, Blaschke G. Enantioseparations in capillary electromigration techniques: recent developments and future trends. J Chromatogr A 2001; 906:309-63. [PMID: 11215895 DOI: 10.1016/s0021-9673(00)01124-9] [Citation(s) in RCA: 264] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review summarizes the current status of enantioseparations using capillary electromigration techniques and gives the authors insights on the selected fundamental aspects and future trends in this field. The most recent developments in the field of chiral separations using capillary electrophoresis (CE) and capillary electrochromatography (CEC) are summarized. The status of chiral electromigration techniques is evaluated tacking into account the most recent developments in related techniques such as chiral HPLC, GC and SFC.
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Affiliation(s)
- B Chankvetadz
- University of Münster, Institute of Pharmaceutical Chemistry, Germany.
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36
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Lämmerhofer M, Zarbl E, Lindner W. Tert.-butylcarbamoylquinine as chiral ion-pair agent in non-aqueous enantioselective capillary electrophoresis applying the partial filling technique. J Chromatogr A 2000; 892:509-21. [PMID: 11045508 DOI: 10.1016/s0021-9673(00)00172-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The potential of tert.-butylcarbamoylquinine as chiral selector (SO) added to a non-aqueous background electrolyte for the capillary electrophoretic separation of the enantiomers of N-derivatized amino acids (selectands, SAs) is evaluated. Separation is based on different ion-pair formation equilibrium constants of (R) and (S) enantiomers of the negatively charged chiral analytes with the positively charged quinine-derived chiral SO and on mobility differences of free and complexed SAs, so that differences in the overall migration behavior of the SA enantiomers result. To suppress problems associated with the high UV absorption of the chiral SO and thus the high detector background in the 'total filling technique', the 'partial filling technique' has been adopted. Several parameters including filling time and length of SO zone, respectively, SO concentration, type of background electrolyte, have been evaluated. Using such an optimized method, for example, (R) and (S) enantiomers of 2,4-dinitrophenyl (DNP)-protected proline could be separated with alpha=1.08, R(S)=6.60, and N=130,000 theoretical plates within 15 min. Similar alpha values, resolution, and efficiencies were observed for other DNP-protected, as well as for diverse, N-derivatized amino acids like N-benzoyl, N-9-fluorenylmethoxycarbonyl, N-3,5-dinitrobenzyloxycarbonyl amino acids. A repeatability study clearly validated the robustness of the method and revealed its practical applicability.
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Affiliation(s)
- M Lämmerhofer
- Institute of Analytical Chemistry, University of Vienna, Austria.
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37
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Chiari M, Cretich M, Desperati V, Marinzi C, Galbusera C, De Lorenzi E. Evaluation of new adsorbed coatings in chiral capillary electrophoresis and the partial filling technique. Electrophoresis 2000; 21:2343-51. [PMID: 10939444 DOI: 10.1002/1522-2683(20000701)21:12<2343::aid-elps2343>3.0.co;2-c] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
When using chiral selectors and the partial filling technique in capillary electrophoresis, a suitable and reproducible suppression of the electroosmotic flow is still a challenging issue, and there are a number of reasons to find alternatives to the use of covalently coated capillaries for such a particular application. In this paper, new achiral, neutral, and water-soluble polymers are evaluated as adsorbed polymers for the suppression of electroosmotic flow (EOF) when employing chiral capillary electrophoresis and the partial filling technique. Four chiral selectors, namely a cationic cyclopeptide, vancomycin, human serum albumin and riboflavin binding protein have been chosen for this study and some analytes such as derivatized amino acids, promethazine and prilocaine have been used as test compounds. Reproducibility of migration times, resolution, and selectivity as well as efficiency are reported to critically evaluate the performance of the adsorbed coatings. Results are compared to parallel data obtained with fused-silica and polyvinyl alcohol-coated capillaries.
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Affiliation(s)
- M Chiari
- Institute of Biocatalysis and Molecular Recognition, CNR, Milan, Italy.
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38
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Mito E, Zhang Y, Esquivel S, Gomez FA. Estimation of receptor-ligand interactions by the use of a two-marker system in affinity capillary electrophoresis. Anal Biochem 2000; 280:209-15. [PMID: 10790302 DOI: 10.1006/abio.2000.4536] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The study of receptor-ligand interactions by affinity capillary electrophoresis (ACE) requires an accurate form of analysis. Here, we examine the use of two noninteracting standards (markers) in the analysis of binding constant data in ACE studies. This concept is demonstrated using two model systems: carbonic anhydrase B (CAB, EC 4.2.1.1) and arylsulfonamides, and vancomycin (Van) from Streptomyces orientalis and the dipeptide N-acetyl-d-Ala-d-Ala. In this procedure a plug of receptor and noninteracting standards is injected, and analysis of the change in the relative migration time ratio of the receptor, relative to the noninteracting standards, as a function of the concentration of the ligand yields a value for the binding constant. The findings described here demonstrate that data from ACE studies can best be analyzed using two noninteracting standards, yielding values comparable to those estimated using other binding and ACE techniques.
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Affiliation(s)
- E Mito
- Department of Chemistry and Biochemistry, California State University, Los Angeles, 5151 State University Drive, Los Angeles, California, 90032, USA
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39
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Mohamed NA, Kuroda Y, Shibukawa A, Nakagawa T, El Gizawy S, Askal HF, El Kommos ME. Enantioselective binding analysis of verapamil to plasma lipoproteins by capillary electrophoresis-frontal analysis. J Chromatogr A 2000; 875:447-53. [PMID: 10839164 DOI: 10.1016/s0021-9673(99)01288-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Capillary electrophoresis coupled with frontal analysis was applied to the study of enantioselective binding of verapamil (VER) to plasma lipoproteins. The drug-lipoprotein mixed solution, which had been in the binding equilibrium, was hydrodynamically introduced into a non-coated fused-silica capillary. Since VER is positively charged in the neutral run buffer (pH 7.4), the unbound VER enantiomers migrated toward the cathodic end much faster than negatively charged lipoproteins and their bound forms. Once unbound VER migrated apart from lipoprotein, the bound VER was quickly released from the protein to maintain the binding equilibrium. Thus, VER migrated as a zone through the capillary and gave a trapezoidal peak with a plateau region on the electropherogram. The VER concentration in this plateau region was equal to the unbound VER concentration in the initial sample solution. It was found that the bindings of VER to high-density lipoprotein (HDL), low-density lipoprotein (LDL) and oxidized LDL were not site-specific and not enantioselective. Partition-like binding to lipid part of these lipoproteins seemed to be dominant. The total binding affinities of LDL to VER were about seven-times stronger than those of HDL, and the oxidation of LDL by copper ion enhanced the binding affinities significantly.
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Affiliation(s)
- N A Mohamed
- Graduate School of Pharmaceutical Sciences, Kyoto University, Japan
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40
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Abstract
The review summarizes the most recent developments in the field of enantioseparation of chiral drugs using capillary electromigration techniques. The basic principles of enantioseparations in CE are discussed. Recent developments in sample introduction, separation and detection in capillary electrophoresis and capillary electrochromatography are summarized. The applications are arbitrarily divided into the following three groups: (a) racemates and artificial mixtures of enantiomers, (b) drug forms and (c) chiral drugs and their metabolites in biological fluids. Among the various techniques involved the relatively new developments such as CEC in aqueous and nonaqueous buffers, on-line CE-MS coupling, etc. are emphasized.
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Affiliation(s)
- G Blaschke
- Institute of Pharmaceutical Chemistry, University of Münster, Germany.
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41
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Haginaka J. Enantiomer separation of drugs by capillary electrophoresis using proteins as chiral selectors. J Chromatogr A 2000; 875:235-54. [PMID: 10839146 DOI: 10.1016/s0021-9673(99)01168-1] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The separation of drug enantiomers using proteins as the chiral selectors in capillary electrophoresis (CE) is considered in this review. The proteins used include albumins such as bovine serum albumin, human serum albumin and serum albumins from other species, glycoproteins such as alpha1-acid glycoprotein, crude ovomucoid, ovoglycoprotein, avidin and riboflavin binding protein, enzymes such as fungal cellulase, cellobiohydrolase I, pepsin and lysozyme and other proteins such as casein, human serum transferrin and ovotransferrin. Protein-based CE is carried out in two modes: in one proteins are immobilized or adsorbed within the capillary, or protein-immobilized silica gels are packed into the capillary (affinity capillary electrochromatography mode), and in the other proteins are dissolved in the running buffer (affinity CE mode). Furthermore, the advantages and limitations of the two modes and the factors affecting the chiral separations of various drugs by protein-based CE are discussed.
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Affiliation(s)
- J Haginaka
- Faculty of Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya, Hyogo, Japan.
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42
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Chapter 9 Recent developments in liquid chromatographic enantioseparation. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1567-7192(00)80012-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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43
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Flow-through partial-filling affinity capillary electrophoresis for the estimation of binding constants of ligands to receptors. Chromatographia 1999. [DOI: 10.1007/bf02497305] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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44
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Abstract
The current status of capillary electrophoresis (CE) in pharmaceutical analyses is reviewed with about 300 references, mainly from 1996 until 1999. This article covers the use of CE for assay and purity determination of the main component, analysis of natural medicines, antisense DNA, peptides, and proteins. Analysis of hydrophobic and/or electrically neutral drugs by electrokinetic chromatography, capillary electrochromatography and nonaqueous CE is critically evaluated. Detailed techniques for the separation of enantiomers are given in the text with some actual applications. Furthermore, this review includes sensitivity and regulatory aspects for the actual use of CE in new drug applications (NDA). The analytical validation required for CE in NDA is also treated.
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Affiliation(s)
- H Nishi
- Analytical Chemistry Department, Tanabe Seiyaku Co., Osaka, Japan.
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45
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Amini A, Paulsen-Sörman U, Westerlund D. Principle and applications of the partial filling technique in capillary electrophoresis. Chromatographia 1999. [DOI: 10.1007/bf02490748] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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46
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Chankvetadze B, Burjanadze N, Pintore G, Strickmann D, Bergenthal D, Blaschke G. Chiral recognition of verapamil by cyclodextrins studied with capillary electrophoresis, NMR spectroscopy, and electrospray ionization mass spectrometry. Chirality 1999; 11:635-44. [PMID: 10467315 DOI: 10.1002/(sici)1520-636x(1999)11:8<635::aid-chir5>3.0.co;2-d] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Capillary electrophoresis (CE) allows the observation of the opposite affinities of the enantiomers of (+/-)-verapamil [2-isopropyl-2,8-bis(3,4-dimethoxyphenyl)-6-methyl-6-azaoctannitrile+ ++, VP] toward beta-cyclodextrin (beta-CD) and heptakis(2,3, 6-tri-O-methyl)-beta-CD (TM-beta-CD). In addition, in the presence of beta-CD in the background electrolyte, longer migration times and lower separation factors were observed compared to TM-beta-CD. The binding constants of (+)- and (-)-VP with beta-CD and TM-beta-CD determined using (13)C NMR spectroscopy explain the results observed in CE. Electrospray ionization mass spectrometry (ESI-MS) was used as an alternative technique for the characterization of VP-CD complexes.
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Affiliation(s)
- B Chankvetadze
- Institute of Pharmaceutical Chemistry, University of Münster, Hittorfstrasse 58-62, 48149 Münster, Germany
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47
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De Lorenzi E, Massolini G, Quaglia M, Galbusera C, Caccialanza G. Evaluation of quail egg white riboflavin binding protein as a chiral selector in capillary electrophoresis by applying a modified partial filling technique. Electrophoresis 1999; 20:2739-48. [PMID: 10532342 DOI: 10.1002/(sici)1522-2683(19990901)20:13<2739::aid-elps2739>3.0.co;2-n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A preliminary evaluation of the enantioselective properties of quail egg yolk riboflavin binding protein (qRfBP) was carried out in capillary electrophoresis by using the complete filling technique. The most promising results obtained by this screening of nineteen chiral drugs were singled out with the aim of optimizing enantiomer separations by applying the partial filling technique, which allows operating at much higher protein concentrations without detection problems. The building of the separation zone in the partial filling technique has been modified in order to enable on-line monitoring, before each run, of the actual protein plug application velocity and, consequently, the building of a plug of the desired length. The electrophoretic conditions chosen gave opposite migration directions for the chiral selector and the analytes, with qRfBP migrating away from the detector. A polyvinyl alcohol-coated capillary was first totally filled with protein and the optimal plug length was obtained by further applying negative pressure together with positive voltage for the time needed. Separations of basic drugs were optimized by using protein concentrations ranging from 200 microM up to 900 microM and different plug lengths, while the running buffer pH (6.0), temperature (25 degrees C) and operating voltage (+20 kV) were kept constant. The enantioresolution of all solutes was affected by both the chiral selector concentration and protein plug length. Baseline separations were obtained for oxprenolol, prilocaine and bupivacaine.
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Affiliation(s)
- E De Lorenzi
- Department of Pharmaceutical Chemistry, University of Pavia, Italy.
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48
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Riboflavin binding proteins as chiral selectors in HPLC and CE. PHARMACEUTICAL SCIENCE & TECHNOLOGY TODAY 1999; 2:352-364. [PMID: 10470023 DOI: 10.1016/s1461-5347(99)00189-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The term riboflavin binding proteins (RfBPs) is applied to several molecular species that play the important role of vitamin delivery to the developing embryo, thus becoming essential for the survival of the fetus. In addition to this physiological significance, these proteins have recently been found to be successful chiral selectors. In this review, the authors address the use of such proteins, both as columns for high performance liquid chromatography (HPLC) and as additives in capillary electrophoresis (CE), for the enantioseparation of several racemic drugs.
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Zhu X, Ding Y, Lin B, Jakob A, Koppenhoefer B. Study of enantioselective interactions between chiral drugs and serum albumin by capillary electrophoresis. Electrophoresis 1999; 20:1869-77. [PMID: 10445329 DOI: 10.1002/(sici)1522-2683(19990701)20:9<1869::aid-elps1869>3.0.co;2-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The separation of the enantiomers of three basic drugs, i.e., ofloxacin, propranolol and verapamil, was achieved by affinity capillary electrophoresis (ACE), with human serum albumin (HSA) and bovine serum albumin (BSA) as chiral selectors in phosphate buffer at pH 7.4. Ofloxacin was only separated in the presence of BSA, and verapamil only with HSA, while propranolol was separated with either HSA or BSA. The effects of protein concentration and column wall adsorption on the degree of separation were investigated. Two displacers, ketoprofen and warfarin, respectively, when added to the protein containing buffer, both showed significant effects on the separation behavior. From these data it was argued that verapamil may bind to HSA at both locations known, the warfarin binding site (I) and the ketoprofen binding site (II). While with BSA, binding of ofloxacin may also occur at site I, the preferential binding site for propanolol remains controversial. A drug-drug interaction between propranolol and ketoprofen due to opposite charges was concluded from the increase in migration time in BSA solution. The unbound concentration of verapamil enantiomers in solution in the presence of HSA, as estimated from CD-modified capillary zone electrophoresis, was triggered not only by the HSA concentration but also by the coadditive concentration.
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Affiliation(s)
- X Zhu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences
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Tahara SI, Okayama A, Kitada Y, Watanabe T, Nakazawa H, Kakehi K, Hisamatu Y. Enantiomeric separation of atropine in Scopolia extract and Scopolia Rhizome by capillary electrophoresis using cyclodextrins as chiral selectors. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00447-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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